Databases
StackOverflow2013
Postsdbo
POhow to modify Knapsack - to find the maximum weighted sum
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POhow to modify Knapsack - to find the maximum weighted sum
    primarykey
    data
    text
    <p>The below is a knapsack code using dynamic programming. The original code will return a maximum sum of the values. However, I want to tweak it so that the code will return a maximum sum of (value*weight). The below is what I have done, but it doesn't work well, some advice is appreciated. </p> <pre><code> #include&lt;stdio.h&gt; int max(int a,int b) { return a&gt;b?a:b; } int Knapsack(int items,int weight[],int value[],int maxWeight) { int dp[items+1][maxWeight+1]; /* dp[i][w] represents maximum value that can be attained if the maximum weight is w and items are chosen from 1...i */ /* dp[0][w] = 0 for all w because we have chosen 0 items */ int iter,w; for(iter=0;iter&lt;=maxWeight;iter++) { dp[0][iter]=0; } /* dp[i][0] = 0 for all w because maximum weight we can take is 0 */ for(iter=0;iter&lt;=items;iter++) { dp[iter][0]=0; } for(iter=1;iter&lt;=items;iter++) { for(w=0;w&lt;=maxWeight;w=w+10) { dp[iter][w] = dp[iter-1][w]*weight[iter-1]; /* If I do not take this item */ if(w-weight[iter] &gt;=0) { /* suppose if I take this item */ dp[iter][w] = max( (dp[iter][w]*weight[iter]) , (dp[iter-1][w-weight[iter]]*weight[iter-1])+(value[iter]*weight[iter])); } } } return dp[items][maxWeight]; } int main() { int items=12; int weight[/*items+1*/13]={60, 20, 20, 20, 10, 20, 10, 10, 10, 20, 20, 10}; int value[/*items+1*/13]={48, 77, 46, 82, 85, 43, 49, 73, 65, 48, 47, 51}; int iter; int maxWeight=120; printf("Max value attained can be %d\n",Knapsack(items,weight,value,maxWeight)); } </code></pre> <p>The code is expected to give an output of <em>Max value attained can be 7820</em> (the maximum total sum of value*weight calculated by hand). However, the output is <em>Max value attained can be 0</em>. Why?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USVoyage_Mystere
    1. USVoyage_Mystere
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POhow to modify Knapsack - to find the maximum weighted sum
      1. This table or related slice is empty.
      1. VTUpMod
    1. COYou should also mention about what you are getting and what is your expected output.
      singulars
      1. POhow to modify Knapsack - to find the maximum weighted sum
      1. UShaccks
    2. COThanks for pointing out, edit it right away~
      singulars
      1. POhow to modify Knapsack - to find the maximum weighted sum
      1. USVoyage_Mystere
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload